The invention relates to a semiconductor device and more particularly, it is preferably applied to a semiconductor device including a fuse element in a semiconductor substrate.
A semiconductor device having a memory formed of a semiconductor element formed in a semiconductor substrate includes that one having a memory cell including an anti-fuse element. This semiconductor device writes data into a memory cell by applying a high voltage between a gate electrode of the anti-fuse element and a source and drain region, to dielectrically break down a gate insulating film of the anti-fuse element. In this writing operation, according to the dielectric breakdown of the gate insulating film of the anti-fuse element, a reading current as a gate leak current increases before and after the writing operation.
The dielectric breakdown of the gate insulating film of the anti-fuse element is performed only once and therefore, the writing into the memory cell including the above anti-fuse element is referred to as One Time Program (OTP). The memory element including the anti-fuse element is referred to as One Time Programmable (OTP) memory element and used for Read Only Memory (ROM).
The anti-fuse element is disclosed in, for example, Japanese Unexamined Patent Application Publication No. 2006-59919, Japanese Unexamined Patent Application Publication NO. 2011-119640, Japanese Unexamined Patent Application Publication No. 2009-54662, and Japanese Unexamined Patent Application Publication No. 2009-200497.